Note Transfers of financial assets and servicing assets (Changes in MSRs measured using the fair value method) (Detail) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017
Transfers and Servicing of Financial Assets
Fair value at beginning of period		$ 168,031	$ 196,889
Additions		4,923	5,839
Changes due to payments of loans	[1]	(6,852)	(9,276)
Reduction due to loan repurchases		(2,077)	(1,102)
Changes in fair value due to changes in valuation model inputs or assumptions		0	(3,622)
Fair value at end of period		$ 164,025	$ 188,728

[1] Represents changes due to collection / realization of expected cash flows over time.